Field of the Invention
The present invention relates to battery management systems that measure and monitor data of batteries in a battery pack, and specifically to battery management systems that transmit battery data wirelessly to a computing device.
Background
Current battery management systems obtain data about individual batteries in a battery unit. The systems reserve addresses for communication with battery unit sensors and/or battery units. When sensors transmit data about battery units to the management system, the sensors include the address of the battery unit. Such a system may require significant amounts or resources and complex arrangements for connecting the components of the system. Additionally, current systems for battery management may require complex, expensive systems for detecting potentially hazardous connections between battery units and their enclosure, such as a chassis in an electric vehicle.
As shown in FIG. 19, lithium batteries have a non-linear discharge profile, with a relatively flat discharge region up to about 80% discharged. Therefore, a small change in voltage can mean a large difference in the state of charge, unlike a lead acid battery that has a relatively linear drop in voltage as the battery is discharged. The state of charge of a lead acid battery, and therefore the amount of power remaining, is more easily monitored by simply measuring the voltage of the lead acid battery. The amount of power remaining in a lithium battery system is more difficult to monitor and predict however by simply measuring voltage. It would therefore be more difficult to determine the available power remaining in a lithium battery unit by simply measuring the voltage.
The wiring of battery management systems with a computing device can be expensive and complicated. The large number of wires may be difficult to route from a battery pack to a computing device. In addition, when a battery has to be changed out, keeping track of the wires and the correct location for installation of a new battery can be very difficult.